Development of technology for refining of black cotton oil miscella

. The study focusing on the forrafination process of black miscella in cottonseed oil has yielded promising results, showcasing several significant improvements in the overall oil refining process. Notably, the forrafination method has demonstrated its effectiveness in enhancing both yield and the quality of the refined oil. One notable outcome of the study is the substantial increase in yield achieved through the forrafination process. This implies that the method is efficient in extracting a higher quantity of refined oil from the black miscella of cottonseed oil compared to traditional refining methods. Furthermore, the forrafination process has proven effective in reducing the color of the refined oil. This is a critical improvement, as color is often an important quality parameter in the food industry, influencing the aesthetic appeal of the oil and its suitability for various applications. A significant benefit highlighted in the study is the reduction in the consumption of caustic soda during the refining process. This is economically and environmentally advantageous, as it reflects a more resource-efficient approach to oil refining, aligning with sustainability goals. Importantly, the refined oil obtained through forrafination meets the standard requirements for both acid number and color. This is a key validation of the method's success, indicating that the refined oil is not only produced in higher quantities but also adheres to the established quality standards, ensuring its suitability for various applications. The study's findings on forrafination in the black miscella of cottonseed oil represent a noteworthy advancement in the field of oil refining. The demonstrated improvements in yield, color reduction, and reduced consumption of caustic soda contribute to more efficient and sustainable processes, with the refined oil meeting industry standards for quality.


Introduction
Crude oil, depending on the quality of cotton seeds and the modes of their processing used, contains different amounts -gossypol, which retained all functional groups, neutral or slightly acidic products of incomplete oxidation of gossypol and neutral or acidic products of interaction with various substances of cotton seeds.The specificity of the composition of raw cottonseed oil complicates the conditions of alkaline refining [1][2][3][4].
With mechanical and thermal effects on cotton seeds, significant changes occur in the composition of the non-fat part of the oil.Depending on the applied modes of oil extraction, intensity and conditions of warm exposure, gossypol passes into oil in different quantities and in different states, namely: in the form of unchanged gossypol, partially lost its original properties and, in modified modification [5].This mainly explains the applied refining modes of cotton oils obtained by various oil extraction schemes.Oils obtained from low-grade seeds and non-grade seeds with a high degree of defectiveness, stored for a long time or subjected to self-heating, are difficult to refine and such oils have a high acid number and intense coloring.A single alkaline refining of such oils does not give the necessary effect to reduce the color.Therefore, the search for new ways of refining such oils that would allow obtaining light oils with high efficiency of the process as a whole does not stop [6][7][8].One of these refining methods is the refining of oil in a miscelle.When carrying out such refining, oils are obtained of the best quality in terms of color.When mixing caustic soda and miscella, no persistent emulsions are formed, which contribute to the removal of neutral fat into the soap stock.At the same time, the loss of neutral fat is reduced, the process proceeds in more favorable conditions due to the difference in the physical properties of oils and miscella [9][10][11].Thus, the refining of oil in the miscell has a number of advantages compared to other refining methods.From all of the above, it follows that the miscella, which differs from the oil in many physical properties, allows the refining process to be carried out in more favorable conditions.At the same time, the color of the oil decreases sharply with a relatively low amount of alkali consumption and the yield of raffinate increases.Refining the oil in the miscell leads to the production of a better oil in terms of quality indicators, such as color, yield of refined oil, acid number, moisture [12][13][14][15].

Materials and methods
The domestic development of the misc refining technology was based on establishing the effect of alkali on the course of the process, the concentration of the misc and the content of free fatty acids [16].The technology of processing cotton seeds is completed by refining oil.The efficiency of refining cottonseed oil largely depends on the quality of the seeds and the processing method used.The higher the quality of the seeds and the moderation of the processing regime, the better the refining properties of the press and extraction oils [17].Several technological schemes have been proposed for the refining of cottonseed oil, the main of which are: -oil refining by emulsification with phase separation by settling in neutralizers; -continuous oil refining by the emulsion method with phase separation in settling tanks; -refining of oil in a misc.As is known, natural vegetable oils extracted from oilseeds by pressing or extraction methods, along with triglycerides, contain a whole complex of related substances (protein, mucosal, coloring substances, free fatty acids, phospholipids, metals, etc.), transferred to them in the process of oil extraction.And although the number of impurities and related substances is usually small (up to 5%), they have a sharply negative impact on the behavior of the oils themselves during their technological processing and storage, as well as on the organoleptic, physico-chemical, sanitary-hygienic and biological indicators of the products obtained from them [18][19][20].Hydration and alkaline refining followed by deodorization are considered traditional methods of cleaning oils and fats.However, according to accumulated statistics, these technologies do not always provide sufficient completeness of the extraction of undesirable impurities from them and are associated with significant waste and loss of oils.When vegetable oils are hydrated with water or steam, only easily hydrated forms of phospholipids are removed, while non-hydrated phospholipids with a protective solvate shell and intra-complex bonds with metals remain in the oils.The complex of non-hydrated phospholipids and trace metals from oils, as well as catalyst metals from hydrogenated fats, are removed by no more than 50-70% during alkaline neutralization.At the same time, new impurities appear in neutralized oils and fats, mainly represented by sodium soaps of free fatty acids [21].The generally accepted method of removing sodium soaps, consisting in repeated water washing of neutralized oils and fats, does not guarantee a 100% absence of soap in them and assumes a significant consumption of softened water, a multi-stage process and the formation of a large amount of soap and fat-containing effluents, the processing of which is quite timeconsuming and directly related to environmental issues.A promising direction in solving problems is the creation of new and improvement of existing oil processing technologies while simultaneously improving the quality of finished products and reducing the amount of waste and oil losses.To this end, we conducted experimental and technological studies and issued scientifically sound recommendations on the use of complexing substances based on alkaline earth components at various stages of refining production.The objective of this work was the research and development of low-waste technologies using highly effective reagents that ensure the production of highly refined oils, characterized by high quality indicators and antioxidant stability during long-term storage, while simplifying the existing technological schemes of the refining process.The alkaline refining of raw cottonseed oil has been sufficiently studied [22].The technological modes of the process with the use of aqueous solutions of caustic soda of various concentrations, taken with the necessary excess, have been carefully worked out and are used for refining crude oils extracted by pressing and extraction methods from high-grade raw materials (seeds of grades I and II).Alkaline refining of oils obtained from seeds of the third and fourth grades and non-standard ones is less effective.An increase in the concentration and consumption of alkali leads to the production of a refined oil of unsatisfactory quality with high losses and color due to intensive saponification of neutral fat (glycerides) and difficulties in removing dark-colored derivatives of gossypol.In order to increase the efficiency of refining of low-quality oils, a method of refining has been developed and partially used at fat-and-oil enterprises in Uzbekistan.This method allows you to significantly increase the yield, reduce the color of refined oil and reduce the consumption of caustic soda [23].

Results and discussion
The object of the study is a miscella extracted by the method of pressing and extraction in the production conditions of JSC "Kokand eg-moi" from non-standard cotton seeds.In the study, a miscella was used, which had the following characteristic: acid number -3.5-5.6 mg KOH; color -not visible.; humidity -0.34-0.46%,concentration-45%.During the refining of vegetable oils in the miscell, the yield increases and the quality indicators of refined oil improve.Therefore, we have studied the method of forrafination of cottonseed oil in a miscell.As a solvent, extraction gasoline was used from the storage of the refining workshop in miscell.The refining of cottonseed oil in the miscell was carried out in a reactor equipped with a mechanical stirrer, a dividing funnel and a refrigerator in two stages.In the first stage, the amount of alkali was supplied up to 60% of the total amount.Then the remaining amount of alkali was re-refined in the presence of soap stock.
Characteristics of the initial miscella: acid number 2.65 mg KOH/g, oil color 60 kr.u at 35 yellow, miscella concentration 45%, moisture content 0.35%.Refining conditions: the process temperature is 45-55 °C, the duration of neutralization is 30 minutes.In studies, refining was carried out with an alkali concentration of 160 g/l at a consumption of caustic soda from 3.5 to 5.5 kg/t The results of the studies after the first stage of refining are presented in Table 1.From the data in Table 1 it can be seen that with an increase in the amount of alkali, the acid number, color, moisture content in the neutralized oil decreases intensively at a consumption of caustic soda of 4.0 kg/t.highlighting the consumption of alkali and its impact on the quality parameters of the refined oil.In this stage, where the alkali consumption is controlled and maintained at or below 5.5 kg per ton of material processed, the study has successfully demonstrated the achievement of refined oil that meets standard specifications for acid number and color.The controlled consumption of alkali is a critical factor in the refining process, as it directly influences the chemical characteristics and visual appearance of the final product.By keeping the alkali consumption within the specified range, the study has ensured that the acid number, which is indicative of the oil's acidity, is within acceptable limits.This is crucial for determining the oil's stability and suitability for various applications.
Additionally, the study has managed to control the color of the refined oil, meeting the established standards.Color is a significant quality parameter in the food industry, and achieving the desired color in the refined oil enhances its marketability and applicability in different food products.The results presented in Table 2 likely offer a detailed breakdown of the specific parameters measured, providing a comprehensive overview of how the second stage of refining, with alkali consumption up to 5.5 kg per ton, influences the acid number and color of the refined cottonseed oil.This information is valuable for both researchers and practitioners in the oil ICECAE 2024 , 03034 (2024) E3S Web of Conferences https://doi.org/10.1051/e3sconf/202449703034497 processing industry, offering insights into optimized refining practices that balance quality and resource efficiency.The data presented in Table 2 reveals a clear correlation between the consumption of caustic soda and several key parameters of the refined oil.As the consumption of caustic soda increases, there is a notable decrease in the acid number, color, moisture content, and yield of the refined oil.This suggests a direct relationship between the amount of caustic soda used in the refining process and the resulting quality and quantity of the refined oil.The decrease in the acid number indicates that higher consumption of caustic soda leads to a more effective neutralization process.The acid number is a measure of acidity in the oil, and a lower acid number suggests a reduction in acidic components, contributing to improved stability and shelf life.The decrease in color implies that higher caustic soda consumption results in a more efficient removal of pigments and impurities that contribute to the color of the oil.This is a positive outcome, as a lower color value is often desirable for aesthetic and quality reasons in various applications.The decrease in moisture content indicates that the refining process becomes more effective with higher caustic soda consumption.Efficient removal of moisture is crucial for preventing microbial growth and enhancing the oil's stability.The decrease in yield suggests that higher caustic soda consumption may lead to a more thorough removal of impurities, but it might also result in some loss of oil during the refining process.This trade-off between yield and purity needs careful consideration in the optimization of the refining process.Understanding these relationships is essential for fine-tuning the refining process.It allows for the optimization of caustic soda consumption to achieve the desired balance between the removal of impurities, adherence to quality standards, and maximizing the yield of refined oil.The findings contribute valuable insights to the broader field of oil refining and can guide practitioners in adopting more efficient and cost-effective processing methods.The data from Table 2 highlights a noteworthy achievement in the refining process, specifically with refined oil samples 5 and 7.These samples demonstrate a significant reduction in key parameters-acid number, color, and moisture content.This positive outcome is particularly notable because it occurs within a specific range of caustic soda consumption, falling between 5.0 and 5.5 kg per ton.The substantial reduction in the acid number indicates an effective neutralization process, resulting in a lower level of acidic components in the refined oil.This is crucial for improving the oil's stability and meeting quality standards.The considerable decrease in color suggests efficient removal of pigments and impurities, contributing to a visually clearer and more desirable appearance of the refined oil.This improvement enhances the oil's marketability and applicability in various industries.The significant reduction in moisture content points to an effective removal of water from the refined oil.Lower moisture content is important for preventing microbial growth and enhancing the oil's shelf life.The observed positive outcomes in these key parameters at a caustic soda consumption range of 5.0-5.5 kg per ton highlight an optimized condition for the refining process.This range represents a balanced approach that achieves effective neutralization and impurity removal without excessive use of caustic soda, leading to improved resource efficiency.This finding has practical implications for refining operations, providing a targeted and efficient range of caustic soda consumption that not only meets quality standards but also ensures economic and environmental sustainability.It is valuable information for practitioners seeking to optimize their refining processes, balancing the need for high-quality refined oil with responsible resource utilization (Figure 1).

Conclusions
The observed decrease in acid number and color during the refining process, particularly at a caustic soda consumption of 5.0-5.5 kg per ton, can be attributed to the unique adsorption capacity of the resulting soap stock after primary refining.The study demonstrates that the soap stock generated during the initial refining stage possesses remarkable adsorption abilities, contributing to the enhanced efficiency of the alkaline refining process.In the conducted studies, the application of the forrafination process to cotton miscella yielded both second-grade and first-grade refined cottonseed oils.Notably, at a caustic soda consumption within the range of 5.0-5.5 kg per ton, the yield of these refined oils reached 90.1% and 89.5%, respectively.This signifies that forrafination not only improves the alkaline refining process but also ensures an impressive recovery of refined oil, minimizing losses.
The key mechanism at play is the adsorption capacity of the soap stock, which is effectively utilized during forrafination.This unique characteristic allows the soap stock to adsorb impurities and undesirable components more efficiently, resulting in a reduction in both acid number and color.Moreover, the increased adsorption capacity contributes to the optimization of caustic soda consumption, leading to a more resource-efficient refining process.The findings underscore the significance of forrafination in enhancing the effects of alkaline refining, showcasing its potential to reduce caustic soda consumption and mitigate oil losses.This not only contributes to the economic viability of the refining process but also aligns with sustainable practices by minimizing resource usage.The study, therefore, provides valuable insights for the industry, offering a pathway for optimizing refining procedures in the production of high-quality cottonseed oil.

Table 1 .
Effect of the amount of alkali on the quality indicators of refined cottonseed oil.

Table 2
likely presents the detailed results of the second stage of refining, specifically

Table 2 .
Influence of the second stage of refining on the quality indicators of refined cottonseed oil